The present invention relates to a shock absorbing type footwear such as, for example, athletic shoes.
This type of conventional footwear has the sole made of an elastic material as used in athletic shoes and rubber-soled shoes to relieve a shock applied to a foot by a shock absorbing action owing to the elasticity of the sole.
However, a shock which is caused upon each step of feet of a running person is remarkably large and therefore a thick shoe sole is required to effectively buffer such shock. A large thickness of the shoe sole is disadvantageous in that the weight of shoes increases and it is difficult to use the shoes.
In other words, if an elastic shoe sole is used to absorb the shock, the sole absorbs the shock by elastic deformation of the part which receives the shock and therefore a repulsive force due to elastic deformation acts on the foot and a large shock cannot be fully absorbed by local deformation of a thin shoe sole. There is a problem that the shock absorbing effect of shoes cannot be demonstrated in hard sports activities.
For this reason, a person who plays hard sports games or walks for many hours everyday such as, for example, athletes or salesmen, will often suffer bone lesion, tendon inflammation, lumbago, deficiency of blood, etc. due to stresses even though they wear the shoes with elastic soles.